1. Field of the Invention
This invention relates to a portable electronic device constructed so that an IC card reader-writer integrated with a battery pack can be attached to the portable electronic device main unit.
2. Description of the Related Art
In portable electronic devices, such as portable phones and videorecorders, power is supplied from a detachable battery pack. In these portable electronic devices, the battery pack needs to be detached for recharge after its capacity has been exhausted. Therefore, an important technical challenge in recent years has been to minimize power consumption to extend the battery life and, thus, the operating time of the portable electronic device.
Attempts are made to combine a portable electronic device and an IC card, to create new applications for portable electronic devices. For example, portable phones, whose service has been expanding dramatically in recent years, can only be used by individual users. However, if they can also be used as public phones, their application would further be expanded. It is believed that the use of IC cards instead of prepaid telephone cards would enable portable phones to be used as public phones. By using the memory of IC cards, which is significantly larger than that of magnetic cards, it is also possible to find new applications that were previously unimaginable.
For this purpose, an IC card reader-writer needs to be connected to the portable phone so that its memory can be accessed. However, if an IC card reader-writer is integrated with the portable phone unit, the portable phone unit would be too expensive for conventional users who use portable phones for individual purposes only and who do not need an IC card reader-writer. Also, the total power consumption would be higher than conventional portable phones because the battery consistently supplies power to the IC card reader-writer although the IC card reader-writer is not in use, which shortens the battery life and, thus, the operating time of the portable phone.